titanium boride (TiB2) is a highly effective ceramic component for use in the aerospace, nuclear, and military industries. TiB2 exhibits outstanding properties including high hardness, low density, and excellent resistance to corrosion. These properties make it suitable for a wide range of applications, including wear resistant pieces, steel matrix reinforcements, wall-tiles in nuclear reactors, and Hall-Heroult cells cathodes.
Several different processing methods have been developed for the fabrication of TiB2: pressureless sintering at 2000 degC, hot pressing, and hot isostatic pressing. The sintering temperature is important because TiB2 has a high melting point, requiring a higher sintering temperature to obtain a sufficiently dense polycrystalline matrix without grain growth.
The sintering temperature also affects the flexural strength of TiB2 as a function of grain size. Fig. 12 illustrates the flexural creep behavior of TiB2 at room temperature as a function of the grain size of TiB2.
Grain growth is limited and densification enhanced by the addition of sintering aids such as Cr, CrB2, C, Ni, NiB, and Fe. These additives have a wide range of mass fractions, which can be reduced to the order of 1% to 10 % by reducing the sintering temperature.
Moreover, the use of ZrO2 has a significant impact on the mechanical properties of the TiC-TiB2 composites. It significantly decreases the porosity and increases the hardness of the composites compared to composites produced using no additives.
The presented study is an important advance in the understanding of the mechanical and thermal properties of TiC-TiB2 composites as a function of density and grain size. It is a valuable reference for future studies of this material.